The present invention relates to a process for producing containers, in which a tube of plasticized synthetic material with at least one partition are formed from the synthetic material. The partition extends continuously in the interior of the tube. The tube and partition are extruded into an opened blow mold. The blow mold is closed. By producing a pressure gradient acting on the tube, the tube is expanded and is placed against the molding wall of the blow mold to form the container.
A process of producing container with a partition is disclosed in DE 1 179 356 A1. In this process, when the blow mold is closed, the back end of the tube during extrusion is welded by weld edges located on the top of the blow mold in a hot-wire welding process. The synthetic material forming the container bottom is separated from the synthetic material which is leaving the overlying extruder means. The tube is expanded by supplying blowing air from the opposite lower end of the blow mold, specifically through the container neck molded on the lower end of the blow mold.
In the execution of the known process, the continued processing necessary for producing finished containers is rather elaborate. Thus, the container before filling must be removed from the blow mold which was opened beforehand and turned so that the container neck is at the top. Other working steps are then necessary for filling and producing a container closure.
An object of the present invention is to provide a process which enables comparatively more efficient production of ready-to-use containers with an internal partition.
This object is achieved in a process according to the present invention by welding the end of the tube which is the front end during extrusion and the front end of the partition to one another by closing the opened blow mold in order to close the container bottom and connect the bottom to the partition. By expanding the tube by supplying blowing air from the end of the closed blow mold which is assigned to the container neck and which is opposite the container bottom, the blowing air on either side of each partition acts to expand and form chambers which are separate from one another in the container.
The top end of the mold cavity of the blow mold is assigned to the container neck. The ends of the tube and of the pertinent partition which are the front ends during extrusion provide the parts of synthetic material which reach the lower end of the blow mold, and are welded to form the container bottom according to the present invention. Accordingly, the expanded container can be further processed within the closed blow mold by carrying out the filling process for each inner container chamber through the container neck after expanding the container by means of blowing air introduced through the container neck on both sides next to each partition, without opening the blow mold or removing the container.
The filling process can be carried out by a combined blowing and filling mandrel or by a separate filling mandrel inserted into the container after withdrawing the blowing mandrel from it.
One special advantage of the process of the present invention is that, after filling the container, the container neck is finish-molded by an additional welding process which takes place with the blow mold still closed. In doing so, at the same time, it can be hermetically sealed with a closure formed by the welding process. This closing can take place by movable top welding jaws or head jaws located on the top of the blow mold. Any desired molding processes and/or closure processes can be carried out. For example, a closure which can be torn off at a scored site or disconnect can be formed, preferably in the form of a rotary lock closure. An outside thread could also be molded on the container neck to form a screw closure with a separate closure element. In the welding process carried out on the container neck, separate closures for each chamber of the container or a closure which closes all chambers of the container jointly can be formed.
Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention.